కార్బన్-14: కూర్పుల మధ్య తేడాలు

పంక్తి 84:
 
=== మొత్తం అన్వేషణ ===
Theభూమి inventoryయొక్క ofబయోస్పియర్ లో కార్బన్ carbon-14 in Earth's biosphere is aboutసుమారు 300 [[Curie|megacuries]]మెగా (11&nbsp;[[Exa-|E]][[Becquerel|Bq]]),క్యూరీస్ ofఉన్నట్లు which mostఅన్వేషించబడినది. isఇది inసముద్రాలలో theఎక్కువగా oceansఉన్నది. <ref>{{cite web|url=http://www.ead.anl.gov/pub/doc/carbon14.pdf|title=Human Health Fact Sheet – Carbon 14|date=August 2005|publisher=Argonne National Laboratory, EVS|archiveurl=https://web.archive.org/web/20110716164724/http://www.ead.anl.gov/pub/doc/carbon14.pdf|archivedate=2011-07-16|deadurl=yes|df=}}</ref> కార్బన్ - 14 కొరకు ఈ క్రింది వివరాలు ఇవ్వబడ్డాయి:<ref name="Choppin">Choppin, G.R.; [[Jan-Olov Liljenzin|Liljenzin, J.O.]] and Rydberg, J. (2002) "Radiochemistry and Nuclear Chemistry", 3rd edition, Butterworth-Heinemann, {{ISBN|978-0-7506-7463-8}}.</ref>
* గ్లోబల్ పరిమాణం : ~8500 PBq (సుమారు 50 [[Tonne|t]])
The following inventory of carbon-14 has been given:<ref name="Choppin">Choppin, G.R.; [[Jan-Olov Liljenzin|Liljenzin, J.O.]] and Rydberg, J. (2002) "Radiochemistry and Nuclear Chemistry", 3rd edition, Butterworth-Heinemann, {{ISBN|978-0-7506-7463-8}}.</ref>
** Atmosphereవాతావరణంలో: 140 PBq (840&nbsp;kg)
* Global inventory: ~8500 PBq (about 50 [[Tonne|t]])
** భౌగోళిక పదార్థాలు:మిగిలినది
** Atmosphere: 140 PBq (840&nbsp;kg)
* అణుపరీక్షల నుండి (1990 వరకు): 220 PBq (1.3 t)
** Terrestrial materials: the balance
* From nuclear testing (till 1990): 220 PBq (1.3 t)
 
=== శిలాజ ఇంధనాలలో ===
 
Manyశిలాజ man-made chemicals are derived from [[fossil fuel]]sఇంధనాలు (suchపెట్రోలు asలేదా [[petroleum]]నేలబొగ్గు) orనుండి [[coal]])మానవుడు inతయారుచేసిన whichరసాయనపదార్థాలో <sup>14</sup>C isబాగా greatlyతక్కువగా depletedఉంటుంది. భూవాతావరణంలోని కొంత భాగంలో శిలాజ ఇంధన ఆక్సీకరణ యొక్క సాపేక్ష విలువకు మొత్తం కార్బన్‌డయాక్సైడ్ వినియోగాన్ని <sup>14</sup>CO<sub>2</sub>--or rather, itsపరిమాణాన్ని relative absence—is therefore used to determine the relative contribution (or [[mixing ratio]]) of fossil fuel oxidation to the total [[carbon dioxide]] in a given region of the Earth'sతెలుసుకోవడానికి [[atmosphere]]ఉపయోగిస్తారు.<ref name="NOAA_ESRL_GMD_Education_and_Outreach">{{cite web|url=http://www.esrl.noaa.gov/gmd/outreach/isotopes/c14tracer.html|title=The Basics: 14C and Fossil Fuels|website=NOAA ESRL GMD Education and Outreach|quote=All other atmospheric carbon dioxide comes from young sources–namely land-use changes (for example, cutting down a forest in order to create a farm) and exchange with the ocean and terrestrial biosphere. This makes 14C an ideal tracer of carbon dioxide coming from the combustion of fossil fuels. Scientists can use 14C measurements to determine the age of carbon dioxide collected in air samples, and from this can calculate what proportion of the carbon dioxide in the sample comes from fossil fuels.|archive-url=https://web.archive.org/web/20150925082306/http://esrl.noaa.gov/gmd/outreach/isotopes/c14tracer.html|archive-date=25 September 2015|access-date=9 Dec 2015}}</ref>
 
Dating a specific sample of fossilized carbonaceous material is more complicated. Such deposits often contain trace amounts of carbon-14. These amounts can vary significantly between samples, ranging up to 1% of the ratio found in living organisms, a concentration comparable to an apparent age of 40,000.<ref>{{cite journal|title=Problems associated with the use of coal as a source of C14-free background material|last=Lowe|first=David|journal=Radiocarbon|year=1989|volume=31|issue=2|pages=117–120|url=https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/1127/1132|deadurl=no|archiveurl=https://web.archive.org/web/20130724153305/https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/1127/1132|archivedate=2013-07-24|df=}}</ref> This may indicate possible contamination by small amounts of bacteria, underground sources of radiation causing the <sup>14</sup>N(n,p) <sup>14</sup>C reaction, direct uranium decay (although reported measured ratios of <sup>14</sup>C/U in uranium-bearing ores<ref>{{cite journal|title=Carbon-14 Abundances in Uranium Ores and Possible Spontaneous Exotic Emission from U-Series Nuclides|last1=Jull|first1=A. J. T.|last2=Barker|first2=D.|last3=Donahue|first3=D. J.|journal=Meteorics|volume=20|year=1985|page=676|bibcode=1985Metic..20..676J}}</ref> would imply roughly 1 uranium atom for every two carbon atoms in order to cause the <sup>14</sup>C/<sup>12</sup>C ratio, measured to be on the order of 10<sup>−15</sup>), or other unknown secondary sources of carbon-14 production. The presence of carbon-14 in the [[isotopic signature]] of a sample of carbonaceous material possibly indicates its contamination by biogenic sources or the decay of radioactive material in surrounding geologic strata. In connection with building the [[Borexino]] solar neutrino observatory, petroleum feedstock (for synthesizing the primary scintillant) was obtained with low <sup>14</sup>C content. In the Borexino Counting Test Facility, a <sup>14</sup>C/<sup>12</sup>C ratio of 1.94×10<sup>−18</sup> was determined;<ref>{{cite journal|doi=10.1016/S0370-2693(97)01565-7|title=Measurement of the <sup>14</sup>C abundance in a low-background liquid scintillator|last=Alimonti|first=G.|journal=Physics Letters B|volume=422|issue=1–4|year=1998|pages=349–358|bibcode=1998PhLB..422..349B|display-authors=etal}}</ref> probable reactions responsible for varied levels of <sup>14</sup>C in different [[petroleum reservoir]]s, and the lower <sup>14</sup>C levels in methane, have been discussed by Bonvicini et al.<ref>Bonvicini, G, Harris, N and Paolone, V, "The chemical history of <sup>14</sup>C in deep oilfields", August 2003. ({{arxiv|hep-ex/0308025}})</ref>
 
=== మానవశరీరంలో ===
"https://te.wikipedia.org/wiki/కార్బన్-14" నుండి వెలికితీశారు